public class CustomerFactory {
   
    public static final String[] names = {"Rob", "Joe", "Julie"};
  
    public static AbstractCustomer getCustomer(String name){
       for (int i = 0; i < names.length; i++) {
          if (names[i].equalsIgnoreCase(name)){
             return new RealCustomer(name);
          }
       }
       return new NullCustomer();
    }
 }